US5663252A - Process for preparing a branched polymer from a vinyl aromatic monomer - Google Patents

Process for preparing a branched polymer from a vinyl aromatic monomer Download PDF

Info

Publication number
US5663252A
US5663252A US08/560,235 US56023595A US5663252A US 5663252 A US5663252 A US 5663252A US 56023595 A US56023595 A US 56023595A US 5663252 A US5663252 A US 5663252A
Authority
US
United States
Prior art keywords
free radical
vinyl aromatic
aromatic monomer
radical initiator
polymerization
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US08/560,235
Other languages
English (en)
Inventor
William C. Pike
Duane B. Priddy
Peter H. T. Vollenberg
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Dow Chemical Co
Original Assignee
Dow Chemical Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to US08/560,235 priority Critical patent/US5663252A/en
Application filed by Dow Chemical Co filed Critical Dow Chemical Co
Priority to ES96938616T priority patent/ES2149508T3/es
Priority to EP96938616A priority patent/EP0862586B1/fr
Priority to CA 2234866 priority patent/CA2234866A1/fr
Priority to PCT/US1996/015954 priority patent/WO1997020862A2/fr
Priority to AU75949/96A priority patent/AU7594996A/en
Priority to BR9611819-9A priority patent/BR9611819A/pt
Priority to DE69609984T priority patent/DE69609984T2/de
Priority to CN96198476A priority patent/CN1214056A/zh
Assigned to DOW BENELUS N.V. reassignment DOW BENELUS N.V. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: VOLLENBERG, PETER H.T.
Assigned to DOW CHEMICAL COMPANY, THE reassignment DOW CHEMICAL COMPANY, THE ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: PIKE, WILLIAM C., PRIDDY, DUANE B.
Assigned to DOW CHEMICAL COMPANY, THE reassignment DOW CHEMICAL COMPANY, THE ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: DOW BENELUX N.V.
Application granted granted Critical
Publication of US5663252A publication Critical patent/US5663252A/en
Priority to MX9804049A priority patent/MX9804049A/es
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08F—MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
    • C08F4/00—Polymerisation catalysts
    • C08F4/28—Oxygen or compounds releasing free oxygen
    • C08F4/32—Organic compounds
    • C08F4/34—Per-compounds with one peroxy-radical

Definitions

  • This invention relates to a process for preparing a branched polymer from a vinyl aromatic monomer.
  • Free radical bulk polymerization is a well known process for preparing polymers from vinyl aromatic monomers.
  • typical initiators used in these processes produce high viscosity, high molecular weight polymer in the early stages of polymerization, which can lead to gelling. Therefore, these processes are conducted at low temperatures, keeping the polymerization rate and viscosity low such that heat can be removed sufficiently and gelling is prevented.
  • Branched polymers have been produced from aromatic monomers in a variety of ways including the use of a vinyl functional initiator, such as n-butyl-t-butylperoxyfumarate, as described in U.S. Pat. No. 4,376,847.
  • a vinyl functional initiator such as n-butyl-t-butylperoxyfumarate
  • branching occurs in the polymerization reactor, causing gels to form. Gels build up in the polymerization reactor after extended periods of continuous operation and lead to reactor fouling.
  • Peritaconates have been used as chain transfer agents to retard the Mw growth in the production of polystyrene, polymethylmethacrylate and polybutylacrylate as described in WO 94/13705 by Nuhuis et al., of Akzo Nobel. Although it is mentioned that these chain transfer agents can also be used as polymerization initiators, the process in Nuhuis et al. produces polymers of low molecular weight, e.g. exemplified as having a Mn of between about 2,200 and 24,000.
  • the present invention is a free radical bulk polymerization process for producing a branched polymer from a vinyl aromatic monomer comprising polymerizing a vinyl aromatic monomer in the presence of a free radical initiator of the formula: ##STR2## wherein R is H, alkyl, aryl, or aralkyl, wherein aralkyl is defined as an aryl group attached to an alkyl group and the alkyl group is attached to the oxygen, any alkyl group contains 1-6 carbon atoms, and R' is alkyl or aryl wherein aryl is an aromatic group containing 1-3 rings.
  • This process produces branched polymers, which can have improved properties over linear polymers in extensional rheology, melt strength, and viscosity. These improved properties can lead to processing advantages when compared to linear polymers.
  • Vinyl aromatic monomers suitable for use according to the present invention include, but are not limited to, those vinyl aromatic monomers previously known for use in polymerization processes, such as those described in U.S. Pat. Nos. 4,666,987, 4,572,819 and 4,585,825.
  • the monomer is of the formula: ##STR3## wherein R" is hydrogen or methyl, Ar is an aromatic ring structure having from 1 to 3 aromatic rings with or without alkyl, halo, or haloalkyl substitution, wherein any alkyl group contains 1 to 6 carbon atoms and haloalkyl refers to a halo substituted alkyl group.
  • Ar is phenyl or alkylphenyl with phenyl being most preferred.
  • Typical vinyl aromatic monomers which can be used include: styrene, alpha-methylstyrene, all isomers of vinyl toluene, especially paravinyltoluene, all isomers of ethyl styrene, propyl styrene, vinyl biphenyl, vinyl naphthalene, vinyl anthracene and the like, and mixtures thereof.
  • the vinyl aromatic monomers may also be combined with other copolymerizable monomers.
  • Such monomers include, but are not limited to acrylic monomers such as acrylonitrile, methacrylonitrile, methacrylic acid, methyl methacrylate, acrylic acid, and methyl acrylate; maleimide, phenylmaleimide, and maleic anhydride.
  • the polymerization may be conducted in the presence of predissolved elastomer to prepare impact modified, or grafted rubber containing products, examples of which are described in U.S. Pat. Nos. 3,123,655, 3,346,520, 3,639,522, and 4,409,369.
  • the initiator used in the process of the present invention is a peritaconate of the formula: ##STR4## wherein R is H, alkyl, or aralkyl, wherein aralkyl is defined as an aryl group attached to an alkyl group which is also attached to the oxygen, any alkyl group contains 1-6 carbon atoms, and R' is alkyl or aryl wherein aryl is an aromatic group containing 1-3 rings.
  • R is H and R' is t-butyl.
  • peritaconates used in the process of the present invention are known compounds and can be made by several known methods, including processes taught in WO 94/13705.
  • the amount of initiator used in the process of the present invention will depend upon the desired Mw of the polymer to be produced. Higher levels of initiator produce lower molecular weight polymers.
  • the initiator is typically present in amounts of from about 10 to about 1500 ppm based on the total weight of starting monomer. Preferably, the initiator is present in amounts from about 100 to about 1400 ppm, more preferably from about 200 to about 1200 ppm, and most preferably from about 300 to about 1000 ppm.
  • initiators may also be present in the process of the present invention in combination with the t-alkylperitaconates described above.
  • examples of other initiators which may be present include but are not limited to t-butylhydroperoxide, ditertiary-butylperoxide, cumene hydroperoxide, dicumylperoxide, 1,1-bis(tertiary-butylperoxy)-3,3,5-trimethylcyclohexane, t-butylperoxybenzoate, 1,1-bis(t-butylperoxy-)cyclohexane, benzoylperoxide, succinoylperoxide and t-butyl-peroxypivilate, and azo compounds such as azo bisisobutyro-nitrile, azobis-2,4-dimethylvaleronitrile, azobiscyclohexanecarbo-nitrile, azobismethyl isolactate and azobiscyanovalerate. Typical amounts
  • chain transfer agents such as thiols and mercaptans, e.g., n-dodecylmercaptan, may also be used in the process of the present invention.
  • the process of the present invention can be conducted in the presence of solvent which is inert for the polymeric material being formed.
  • Solvents useful in the process of the present invention include but are not limited to ethyl benzene, benzene, toluene, and the like.
  • the peritaconate initiator can be added to the vinyl aromatic monomer at any time during the polymerization process. It is typically added to the starting monomer(s) prior to polymerization or in the early stages of polymerization, e.g. up to 50% conversion. Preferably, the initiator is dissolved in a solvent and combined with starting monomer(s) prior to the polymerization reaction.
  • Polymerization processes and process conditions for the polymerization of vinyl aromatic monomers are well known in the art. Although any polymerization process can be used, typical processes are continuous bulk or solution polymerizations as described in U.S. Pat. No. 2,727,884 and U.S. Pat. No. 3,639,372 which are incorporated herein by reference.
  • the polymerization is typically conducted at temperatures from about 80° to about 170° C., preferably from about 90° to about 160° C., more preferably from about 100° to about 155° C., and most preferably from about 110° to about 150° C.
  • the polymer produced by the process of the present invention can have a broad range of weight average molecular weight (Mw), ranging from about 75,000 to about 800,000 as measured by gel permeation chromatography (GPC); typically from about 90,000, preferably from about 100,000, more preferably from about 150,000, and most preferably from about 200,000 to about 700,000, preferably to about 600,000, more preferably to about 550,000 and most preferably to about 500,000.
  • Mw weight average molecular weight
  • the polymers produced by the process of the present invention can find use in foam board, foam sheet and injection molded and extruded products.
  • the following examples are provided to illustrate the present invention. The examples are not intended to limit the scope of the present invention and they should not be so interpreted. Amounts are in weight parts or weight percentages unless otherwise indicated.
  • the polymer weight average molecular weight (Mw) is determined using gel permeation chromatography (GPC) and refers to the Mw of the solids. Number average molecular weight (Fin) and (Mz) are also determined using (GPC).
  • Stock solutions are prepared by dissolving 0.0966 g of t-butylperoxybenzoate (tBPB) and 0.0815 g of benzoyl peroxide (BPO) in 210 g of styrene (Sol. 1), 0.0179 g of t-butylperitaconate (tBPIT) in 79.5 g of Sol. 1 (Sol. 2), 0.0355 g of tBPIT in 75.7 g of Sol. 1 (Sol. 3), and 0.0788 g of tBPIT in 101.9 g of styrene (Sol. 4) Approximately 2-3 mls of each solution are placed in two ampoules (12 ⁇ 0.4 in. OD) (0.11 in. wall thickness).
  • tBPB t-butylperoxybenzoate
  • BPO benzoyl peroxide
  • the ampoules are sealed under vacuum using the freeze-thaw technique and heated in an oil bath at 90° C. for 1 hour, followed by raping to 140° C. at a rate of 1° C./minute and holding at 140° C. for 1 hour.
  • the polymer is removed from the ampoule at the appropriate time during the heating treatment as detailed in Table 1 and evaluated.
  • the time listed in Table 1 refers to the time from the beginning of the initial heating at 90° C. Results are listed in Table 1.
  • Mw, Mz and polydispersity all increase by the addition of tBPIT to the feed, when compared with the results obtained with BPO and tBPB alone.
  • Ampoule samples are Prepared as in Example 1 using tBPIT and t-butylperoxy-n-butylfumarate (BPBF)(Comparative example) as initiators and are subjected to the following heat treatment: placing in an oil bath at 90° C. and ramping to 140° C. at 10° C./hour.
  • the polymer is removed from the ampoule at the appropriate time during the heating treatment as detailed in Table 2 and evaluated for Mw, percent solids etc.
  • the time listed in Table 2 refers to the time from initial heating at 90° C. Results are listed in Table 2.
  • Mw continues to build when using BPIT whereas Mw drops off after about 40% conversion when using BPBF.
  • Styrene (1350 g), ethylbenzene (150 g) and an initiator are placed in a 1500 milliliter (mL) reactor which is described in FIG. 1 of U.S. Pat. No. 4,239,863.
  • the initiators are 1,1-bis(t-butylperoxy)cyclohexane (BBPC)(300 ppm), t-butyl peroxybenzoate (tBPB) (500 ppm), 2,2-bis-(4,4-di(t-butylperoxy) cyclohexyl)propane (PK12)(300 ppm), and t-butylperitaconate (tBPIT)(500 ppm).
  • the mixture is heated to 100° C. over 50 min and then to 150° C. at a rate of 10° C./hour. Samples are drawn periodically from the polymerization and analyzed for percent polystyrene and weight average molecular weight using GPC. Results are shown in Table 3.

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)
  • Polymerization Catalysts (AREA)
  • Polymerisation Methods In General (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
US08/560,235 1995-11-21 1995-11-21 Process for preparing a branched polymer from a vinyl aromatic monomer Expired - Fee Related US5663252A (en)

Priority Applications (10)

Application Number Priority Date Filing Date Title
US08/560,235 US5663252A (en) 1995-11-21 1995-11-21 Process for preparing a branched polymer from a vinyl aromatic monomer
CN96198476A CN1214056A (zh) 1995-11-21 1996-10-03 由乙烯基芳族单体制备支化聚合物的方法
CA 2234866 CA2234866A1 (fr) 1995-11-21 1996-10-03 Procede de preparation de polymere ramifie a partir d'un monomere vinylique aromatique
PCT/US1996/015954 WO1997020862A2 (fr) 1995-11-21 1996-10-03 Procede de preparation de polymere ramifie a partir d'un monomere vinylique aromatique
AU75949/96A AU7594996A (en) 1995-11-21 1996-10-03 A process for preparing a branched polymer from a vinyl aromatic monomer
BR9611819-9A BR9611819A (pt) 1995-11-21 1996-10-03 Processo de polimerização por radical livre
ES96938616T ES2149508T3 (es) 1995-11-21 1996-10-03 Un procedimiento para preparar un polimero ramificado a partir de un monomero vinil-aromatico.
EP96938616A EP0862586B1 (fr) 1995-11-21 1996-10-03 Procede de preparation de polymere ramifie a partir d'un monomere vinylique aromatique
DE69609984T DE69609984T2 (de) 1995-11-21 1996-10-03 Verfahren zur herstellung einer verzweigtes polymer von ein vinylaromatisches monomer
MX9804049A MX9804049A (es) 1995-11-21 1998-05-21 Procedimiento para preparar un polimero ramificado a partir de un monomero aromatico de vinilo.

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US08/560,235 US5663252A (en) 1995-11-21 1995-11-21 Process for preparing a branched polymer from a vinyl aromatic monomer

Publications (1)

Publication Number Publication Date
US5663252A true US5663252A (en) 1997-09-02

Family

ID=24236925

Family Applications (1)

Application Number Title Priority Date Filing Date
US08/560,235 Expired - Fee Related US5663252A (en) 1995-11-21 1995-11-21 Process for preparing a branched polymer from a vinyl aromatic monomer

Country Status (9)

Country Link
US (1) US5663252A (fr)
EP (1) EP0862586B1 (fr)
CN (1) CN1214056A (fr)
AU (1) AU7594996A (fr)
BR (1) BR9611819A (fr)
DE (1) DE69609984T2 (fr)
ES (1) ES2149508T3 (fr)
MX (1) MX9804049A (fr)
WO (1) WO1997020862A2 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6353066B1 (en) 2001-02-09 2002-03-05 Fina Technology, Inc. Method for producing copolymers in the presence of a chain transfer agent
WO2007024637A3 (fr) * 2005-08-22 2009-04-23 Fina Technology Mesure et preparation de polymeres vinyliques reticules
US20140256898A1 (en) * 2011-10-27 2014-09-11 Changzhou University Process for preparing branched polymer
US11370861B2 (en) 2018-12-03 2022-06-28 Trinseo Europe Gmbh Chain expended or branched copolymers of vinylidene aromatic monomer and unsaturated compounds with electrophilic groups
US11649347B2 (en) 2019-10-08 2023-05-16 Trinseo Europe Gmbh Impact modified copolymers of (meth)acrylate esters and/or free radically polymerizable monomers containing nucleophilic groups

Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA453158A (fr) * 1948-12-07 The Distillers Company Limited Polymerisation de styrolene et composes apparentes
US2661363A (en) * 1952-01-18 1953-12-01 Shell Dev Peresters of peroxycarboxylic acids
US3451989A (en) * 1965-07-09 1969-06-24 Nat Distillers Chem Corp Peroxy compounds,and polymerization of ethylenically unsaturated hydrocarbons using same as catalysts
US3451981A (en) * 1966-06-29 1969-06-24 Nat Distillers Chem Corp Polymerization of vinyl chloride and mixtures of vinyl acetate and ethylene using tertiary alkyl per-3-alkenoates as catalysts
DE1720770A1 (de) * 1968-01-02 1971-07-15 Elemer Dr Faltusz Verfahren zur Polymerisation von olefinisch ungesaettigten,organischen Verbindungen
US4045463A (en) * 1975-04-04 1977-08-30 Nippon Oil And Fats Co., Ltd. Peroxyesters of sorbic acid
JPS5734102A (en) * 1980-08-08 1982-02-24 Asahi Chem Ind Co Ltd Polymer, polymerization initiator and production thereof
US4376847A (en) * 1980-04-21 1983-03-15 Mitsui Toatsu Chemicals, Inc. Process for the production of styrene polymers
US4520180A (en) * 1982-09-20 1985-05-28 Gaf Corporation Polymerization of vinylpyrrolidone to various molecular weights using a single initiator system consisting essentially of t-Butylperoxypivalate
US5037915A (en) * 1986-12-08 1991-08-06 Berol Nobel Ab Ester of monoperoxy oxalic acid as polymerization initiators
WO1994013705A1 (fr) * 1992-12-04 1994-06-23 Akzo Nobel N.V. Procede de regulation du poids moleculaire dans des (co)polymeres

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH0372505A (ja) * 1989-05-24 1991-03-27 Sanyo Chem Ind Ltd 電子写真用トナーバインダー

Patent Citations (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA453158A (fr) * 1948-12-07 The Distillers Company Limited Polymerisation de styrolene et composes apparentes
US2661363A (en) * 1952-01-18 1953-12-01 Shell Dev Peresters of peroxycarboxylic acids
US3451989A (en) * 1965-07-09 1969-06-24 Nat Distillers Chem Corp Peroxy compounds,and polymerization of ethylenically unsaturated hydrocarbons using same as catalysts
US3451981A (en) * 1966-06-29 1969-06-24 Nat Distillers Chem Corp Polymerization of vinyl chloride and mixtures of vinyl acetate and ethylene using tertiary alkyl per-3-alkenoates as catalysts
DE1720770A1 (de) * 1968-01-02 1971-07-15 Elemer Dr Faltusz Verfahren zur Polymerisation von olefinisch ungesaettigten,organischen Verbindungen
US4045463A (en) * 1975-04-04 1977-08-30 Nippon Oil And Fats Co., Ltd. Peroxyesters of sorbic acid
US4376847A (en) * 1980-04-21 1983-03-15 Mitsui Toatsu Chemicals, Inc. Process for the production of styrene polymers
JPS5734102A (en) * 1980-08-08 1982-02-24 Asahi Chem Ind Co Ltd Polymer, polymerization initiator and production thereof
US4520180A (en) * 1982-09-20 1985-05-28 Gaf Corporation Polymerization of vinylpyrrolidone to various molecular weights using a single initiator system consisting essentially of t-Butylperoxypivalate
US5037915A (en) * 1986-12-08 1991-08-06 Berol Nobel Ab Ester of monoperoxy oxalic acid as polymerization initiators
WO1994013705A1 (fr) * 1992-12-04 1994-06-23 Akzo Nobel N.V. Procede de regulation du poids moleculaire dans des (co)polymeres

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
Dpov. Akad. Nauk Ukr. RSR, Ser. B 29(3), 243 7 (1967) (Ukrain) Vysokomol. Soedin, Ser. A 1970, 12(1), 248 51 (Russ). *
Dpov. Akad. Nauk Ukr. RSR, Ser. B 29(3), 243-7 (1967) (Ukrain) Vysokomol. Soedin, Ser. A 1970, 12(1), 248-51 (Russ).

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6353066B1 (en) 2001-02-09 2002-03-05 Fina Technology, Inc. Method for producing copolymers in the presence of a chain transfer agent
WO2007024637A3 (fr) * 2005-08-22 2009-04-23 Fina Technology Mesure et preparation de polymeres vinyliques reticules
US20140256898A1 (en) * 2011-10-27 2014-09-11 Changzhou University Process for preparing branched polymer
US9181374B2 (en) * 2011-10-27 2015-11-10 Changzhou University Process for preparing branched polymer
US11370861B2 (en) 2018-12-03 2022-06-28 Trinseo Europe Gmbh Chain expended or branched copolymers of vinylidene aromatic monomer and unsaturated compounds with electrophilic groups
US11649347B2 (en) 2019-10-08 2023-05-16 Trinseo Europe Gmbh Impact modified copolymers of (meth)acrylate esters and/or free radically polymerizable monomers containing nucleophilic groups

Also Published As

Publication number Publication date
MX9804049A (es) 1998-09-30
AU7594996A (en) 1997-06-27
ES2149508T3 (es) 2000-11-01
DE69609984D1 (de) 2000-09-28
CN1214056A (zh) 1999-04-14
WO1997020862A2 (fr) 1997-06-12
BR9611819A (pt) 1999-12-14
WO1997020862A3 (fr) 1997-10-16
EP0862586A2 (fr) 1998-09-09
DE69609984T2 (de) 2001-04-12
EP0862586B1 (fr) 2000-08-23

Similar Documents

Publication Publication Date Title
US4918159A (en) Styrene-based/polymercaptan polymer and process for production thereof
US4456736A (en) Method of manufacturing graft copolymers comprising polyphenylene ether
US4328329A (en) Process for polymerizing methyl methacrylate syrup using a dual initiator system
US5115055A (en) Hydroperoxide catalyzed free radical polymerization of vinyl aromatic monomers
US5663252A (en) Process for preparing a branched polymer from a vinyl aromatic monomer
AU730639B2 (en) Improved acid catalyzed polymerization
JPH0830096B2 (ja) 射出成形材料
US5145924A (en) Free radical polymerization of styrene monomer
US5962605A (en) High molecular weight polystyrene production by vinyl acid catalyzed free radical polymerization
RU2352591C2 (ru) Способ получения винилароматических (со)полимеров, привитых на эластомере регулируемым путем
JPH0692471B2 (ja) 熱可塑性組成物の製造方法
US5455321A (en) Process for producing high molecular weight monovinylidene aromatic polymers
US6084044A (en) Catalyzed process for producing high molecular weight monovinylidene aromatic polymers
WO1981001291A1 (fr) Procede de production d'une resine de la serie des styrenes
US4088712A (en) Process for preparing impact resistant polyvinyl aromatics
JP2000501141A (ja) ビニル芳香族モノマーからの枝分かれポリマーの製造方法
US6156855A (en) Production of branched polymers
JPH07116262B2 (ja) α−メチルスチレン共重合体の製造方法
JPS63273606A (ja) 低分子量スチレン系重合体の製造方法
US5079322A (en) Multifunctional cyclobutarene peroxide polymerization initiators
WO1999038894A1 (fr) Procede de production de polymeres aromatiques monovinylidene a volatilite reduite
WO1992013904A1 (fr) Polymerisation de radicaux libres de monomeres de vinyle aromatiques
US6107407A (en) Process for preparing of moulding compounds, modified by acrylic rubber, using groups introduced into said acrylic rubber, which groups are decomposed by a redox constituent to form radicals
JPH0819170B2 (ja) スチレン系重合体の製造方法
US4175101A (en) Acrylonitrile block terpolymer barrier resins

Legal Events

Date Code Title Description
AS Assignment

Owner name: DOW CHEMICAL COMPANY, THE, MICHIGAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:PIKE, WILLIAM C.;PRIDDY, DUANE B.;REEL/FRAME:008477/0165

Effective date: 19951121

Owner name: DOW BENELUS N.V., NETHERLANDS

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:VOLLENBERG, PETER H.T.;REEL/FRAME:008496/0324

Effective date: 19951130

Owner name: DOW CHEMICAL COMPANY, THE, MICHIGAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:DOW BENELUX N.V.;REEL/FRAME:008477/0161

Effective date: 19960925

FEPP Fee payment procedure

Free format text: PAYOR NUMBER ASSIGNED (ORIGINAL EVENT CODE: ASPN); ENTITY STATUS OF PATENT OWNER: LARGE ENTITY

FPAY Fee payment

Year of fee payment: 4

REMI Maintenance fee reminder mailed
LAPS Lapse for failure to pay maintenance fees
STCH Information on status: patent discontinuation

Free format text: PATENT EXPIRED DUE TO NONPAYMENT OF MAINTENANCE FEES UNDER 37 CFR 1.362

FP Lapsed due to failure to pay maintenance fee

Effective date: 20050902